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For microbiology

Microbiology
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1. Advanced Medical Laboratory
Instruments
Student: Mohammed AL-labni
 
2024- 2025
VITEK 2 system

2. VITEK 2 system
The VITEK 2 system is an automated microbial identification and antibiotic
susceptibility testing system used in clinical microbiology laboratories. It is
produced by bioMérieux and is widely employed to identify bacteria and
fungi and determine their resistance or susceptibility to various antibiotics.
Key Features:
1.Automated Identification:
The VITEK 2 system identifies microorganisms (like bacteria and yeast) using
biochemical reactions. It can differentiate hundreds of species based on how
they react to various substrates.

3. 2. Antibiotic Susceptibility Testing (AST):
The system also performs susceptibility tests, which help determine which
antibiotics are most effective against the identified microorganism. This is
crucial for choosing the right treatment for infections

4. 3. Short Turnaround Time:
It provides rapid results, often within a few hours for some tests, compared
to traditional methods that may take 24-48 hours or longer.
4. Compact Cards:
The system uses small plastic cards containing wells with different
substrates for identification and antibiotic testing. Microbial growth or lack
of growth in these wells is analyzed to determine the results.
5. Software:
The VITEK 2 system is supported by software that interprets the data from
the cards, provides reports, and assists with decision-making for clinicians

8. Principle for VITEK 2 System :
-Microbial Identification Database Comparison:
VITEK 2 compares the biochemical reactions of an unknown microorganism to a comprehensive
database of known species to identify the organism.
-Biochemical Tests:
The system uses a series of biochemical tests to determine the metabolic properties of the
microorganism. Each test looks at the organism's ability to ferment carbohydrates, utilize amino
acids, or produce specific enzymes.
-Card Usage:
The system utilizes pre-packaged disposable plastic cards, each containing multiple small wells
with specific substrates or biochemical reagents. When a microorganism is added to the card, it
interacts with the substrates, causing color changes or turbidity based on metabolic activity.

10. procedure for VITEK 2 system :
The VITEK 2 system procedure involves several key steps, from sample
preparation to automated analysis. Below is an outline of the general
workflow for using the VITEK 2 system, both for microbial identification and
antimicrobial susceptibility testing (AST).

12. 1.Sample Preparation :
-Isolate the Organism:
A pure culture of the organism must first be obtained from the patient's
specimen (e.g., urine, blood, sputum) by streaking it on a suitable agar
plate and incubating it.
-Suspension Preparation:
After incubation, a single colony from the pure culture is selected and
suspended in a sterile saline solution (typically 0.45-0.50% NaCl). The
turbidity of the suspension is adjusted to match a standard
concentration, usually 0.5 McFarland standard (for bacteria) or 2.0
McFarland standard (for yeast), using a densitometer.

13. 2. Inoculation of the VITEK 2 Cards
-Card Selection:
The appropriate VITEK 2 card is selected based on the type of
microorganism.
-Common card types include :
ID cards for identification (e.g., GN for Gram-negative bacteria, GP
for Gram-positive bacteria

15. interpretation :
Here’s a general interpretation of the results generated by the VITEK 2
system:
1.Identification Results:
- Confidence Levels:
The system provides a confidence level for each identification.
A higher confidence level (e.g., 90% or above) suggests a reliable
identification, while lower levels may indicate a need for further testing or a
more detailed analysis.
- Species Identification:
The results will list possible species identified based on the metabolic
profile. Clinicians should consider the context of the sample (clinical
relevance, history, etc.) when interpreting results.

16. 2. Antimicrobial Susceptibility Testing (AST) Results:
-Susceptible (S):
Indicates that the organism is likely to be inhibited by the antibiotic at the
concentrations typically achievable in the body.
-Intermediate (I):
The organism may be inhibited by the antibiotic at higher doses; clinical
effectiveness is uncertain.
-Resistant (R):
The organism is not inhibited by the antibiotic, indicating treatment may not
be effective.
-MIC (Minimum Inhibitory Concentration):
The lowest concentration of an antibiotic that prevents visible growth of the
organism; provides quantitative data for susceptibility.

17. 3. Interpretation of Resistance Mechanisms:
VITEK 2 may provide alerts or notes about known resistance mechanisms
(e.g., beta- lactamase production).
These notes guide clinicians in choosing appropriate therapies.
4. Quality Control:
Results should be monitored with regular quality control tests to ensure
reliability. Outlier results or unexpected patterns may indicate issues with
the testing process.
5. Clinical Context:
Always interpret results within the clinical context, including patient
symptoms, history, and local resistance patterns. Consider additional
testing for complex cases.

18. Applications :
-Clinical Laboratories:
To diagnose infections and guide treatment.
-Research Labs:
For microbiological studies.
-Public Health:
In epidemiological surveillance of antibiotic resistance

19. Conclusion:
The VITEK 2 system provides crucial information for diagnosing infections
and guiding effective treatment options. Clinicians should integrate VITEK
results with other diagnostic information for the best patient care

20. THANK YOU